### 1/2mv^2

Posted:

**Fri Oct 13, 2017 3:06 pm**I have been confused with this equation what exactly does this represent can someone explain this to me please?

Created by Dr. Laurence Lavelle

https://lavelle.chem.ucla.edu/forum/

https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=27&t=22181

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Posted: **Fri Oct 13, 2017 3:06 pm**

I have been confused with this equation what exactly does this represent can someone explain this to me please?

Posted: **Fri Oct 13, 2017 3:12 pm**

This equation is for kinetic energy. The total energy of a photon is composed of two energies: threshold and kinetic. The threshold energy is the energy needed to free or move an electron. The kinetic energy is the remaining energy, assuming the energy of the photon is greater than the threshold energy. 1/2mv^2 is the way to calculate the kinetic energy.

Posted: **Fri Oct 13, 2017 3:16 pm**

1/2mv^2 is utilized to find the Kinetic Energy. In the Photoelectric Effect, the energy required to remove the electron is subtracted from the energy of the photon. The difference gives you the excess energy which is equal to the Kinetic Energy of the electron. So, E(Photon)-E(Energy to remove e-)=E(Excess)=Kinetic Energy(e-).